OSLO (Reuters) - Six of the world's eight bear species are under threat of extinction after the addition on Monday of the sun bear, the world's smallest type of bear, to a "Red List" which says China's panda is most at risk.

The sun bear is threatened partly by poachers who sell its gall bladder bile in China as a traditional medicine, said the World Conservation Union which runs the list of threatened wildlife.

ADVERTISEMENT

"Things are getting worse for all the bear species except the American black bear which is unquestionably increasing," said Simon Stuart, senior species adviser for the Union.

The addition of the sun bear to the authoritative Red List after a major review means the American black bear and the brown bear, found from Europe to Alaska, are the only two of eight species still considered robust.

The sun bear, found in Asia from Bangladesh to Borneo and weighing up to about 70 kg (150 lb), was rated "vulnerable" by experts at the Union, which comprises more than 80 governments, conservation groups and scientists.

The sun bear, named after a yellow crescent on its chest, had not previously been listed because of a lack of data. The Union said there were several thousand sun bears in the wild.

"We estimate that sun bears have declined by at least 30 percent over the past 30 years ... and continue to decline at this rate," said Ron Steinmetz, head of the Swiss-based Union's sun bear expert team.

Scientists did not change the level of threat to any other bear species. Deforestation, loss of habitat to roads and cities and poaching are among risks.

The Asiatic black bear, the sloth bear and the Andean bear were all reaffirmed as vulnerable after the reassessment of land-living bears. The polar, the only species not reassessed, is separately rated as vulnerable.

BAMBOO

Pandas were reaffirmed as endangered, one step closer to extinction than vulnerable, despite China's protection efforts for the bamboo-eaters. There are an estimated 1,000-2,000 in the wild, fewer than any other bear species.

"Even though some people have claimed that panda populations are on the rise, we still consider them endangered because too much uncertainty exists to justify changing their status to vulnerable," David Garshelis, co-chair of the Union's bear specialist group, said in a statement.

"The fact that six of eight bear species are under threat is bad news for species that are generally resilient and hang on under human pressure," Stuart told Reuters. Many bears were unfussy eaters and could live in a wide range of habitats.

The brown bear, including grizzly bears, and the American black bear are listed as of "least concern," meaning populations are robust. There are more than 900,000 black bears -- more than twice as many as all other species of bears combined.